Bone and joint infections due to melioidosis; diagnostic and management strategies to optimise outcomes

Abstract

Background: Melioidosis, a life-threatening infection caused by the gram negative bacterium Burkholderia pseudomallei, can involve almost any organ. Bone and joint infections (BJI) are a recognised, but incompletely defined, manifestation of melioidosis that are associated with significant morbidity and mortality in resource-limited settings.

Methodology/principal findings: We identified all individuals with BJI due to B. pseudomallei managed at Cairns Hospital in tropical Australia between January 1998 and June 2023. The patients' demographics, their clinical findings and their treatment were correlated with their subsequent course. Of 477 culture-confirmed cases of melioidosis managed at the hospital during the study period, 39 (8%) had confirmed BJI; predisposing risk factors for melioidosis were present in 37/39 (95%). However, in multivariable analysis only diabetes mellitus was independently associated with the presence of BJI (odds ratio (95% confidence interval): 4.04 (1.81-9.00), p = 0.001). BJI was frequently only one component of multi-organ involvement: 29/39 (74%) had infection involving other organs and bacteraemia was present in 31/39 (79%). Of the 39 individuals with BJI, 14 (36%) had osteomyelitis, 8 (20%) had septic arthritis and 17 (44%) had both osteomyelitis and septic arthritis; in 32/39 (83%) the lower limb was involved. Surgery was performed in 30/39 (77%). Readmission after the initial hospitalisation was necessary in 11/39 (28%), 5/39 (13%) had disease recrudescence and 3/39 (8%) had relapse; 4/39 (10%) developed pathological fractures. ICU admission was necessary in 11/39 (28%) but all 11 of these patients survived. Only 1/39 (3%) died, 138 days after admission, due to his significant underlying comorbidity.

Conclusions: The case-fatality rate from melioidosis BJI in Australia's well-resourced health system is very low. However, recrudescence, relapse and orthopaedic complications are relatively common and emphasise the importance of collaborative multidisciplinary care that includes early surgical review, aggressive source control, prolonged antibiotic therapy, and thorough, extended follow-up.

Fig 1. Anatomical distribution of the osteomyelitis and septic arthritis in the cohort.

n = number of patients. Note: some patients had multiple sites involved. Figure created with BioRender.com.

Fig 2. Magnetic resonance imaging demonstrating osteomyelitis.

(A) Humeral head osteomyelitis and sympathetic joint effusion (B) Mid femoral osteomyelitis with residual abscess (C) Distal tibial osteomyelitis with abscess formation in lateral aspect of distal tibia.

Fig 3. Imaging findings in patient with osteomyelitis of right femoral neck.

(A) Plain x-ray on day 3 of admission which showing no radiological evidence of osteomyelitis (B) PET-CT imaging on day 9 of admission demonstrating osteomyelitis of right femoral neck (arrowed) (C) MRI imaging on day 13 of admission demonstrating osteomyelitis of right femoral neck (arrowed).

Fig 4. Pathological fracture of distal tibia.

(A) plain x-ray (B) CT (C) MRI.